A conventional light source, such as a halogen lamp or an incandescent lamp, when dimmed, acts like a near exact black body radiator and follows the Planckian curve on the 1931 CIE Chromaticity Diagram. For example, a conventional halogen lamp at its maximum output may output light having a color temperature of 2600K. As that halogen lamp is dimmed, the current running through its tungsten filament is reduced, resulting in a lower, warmer color temperature (e.g., 2000K). Because such dimming results in more red light being included in the output of the lamp, such dimming is typically known as red dimming.
As solid state light sources become more widely used, lighting designers and lighting consumers desire that the solid state light sources behave similarly to conventional light sources. Unlike a halogen lamp, however, as a solid state light source is dimmed, it typically holds its color temperature. This has been overcome to a degree by using a color mixing technique. For example, a solid state light source that generates white light and a solid state light source that generates orange/red light (e.g., 590 nm or substantially 590 nm) may both be placed inside a lighting device. At maximum output, only the white light-generating solid state light source is on. As the output is dimmed, the orange/red light-generating solid state light source is turned on and its intensity is increased, with a corresponding decrease in the white light-generating solid state light source. This mimics the effect of red dimming and the color temperature of the dimmed light output exactly, or nearly exactly, follows the Planckian curve.